MALAT1 Regulated mTOR-Mediated Tau Hyperphosphorylation by Acting as a ceRNA of miR144 in Hippocampus Cells Exposed to High Glucose.

AIM: High glucose (HG)-induced activation of mTOR promotes tau phosphorylation and leads to diabetes-associated dementia. This study aimed to explore the role of metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) in HG-induced neuronal cell injury. METHODS: Hippocampus cells were isolated from C57BL/6J mice. After 6 days of culture, the cells were incubated with 5.5 mM glucose in normal medium or 75 mM glucose for 4 days. Cells were transfected with miR-144 mimic, miR-144 inhibitor, siRNA for MALAT1 or corresponding controls. Gene expression was detected by PCR and Western blot analysis. RESULTS: HG increased the levels of MALAT1 and p-tau in hippocampal cells. Knockdown of MALAT1 partially reversed the effects of HG on mTOR activity and p-tau protein levels. MALAT1 functioned as competing endogenous RNA (ceRNA) for miR-144, and pre-treatment with MALAT1 siRNA decreased mTOR activity and p-tau protein level in HG-treated hippocampal cells, which was significantly attenuated by miR-144 mimics. Moreover, miR-144 negatively regulated the expression of mTOR and knockdown of MALAT1 suppressed mTOR, while overexpression of mTOR abrogated protective effects of MALAT1 knockdown in HG-treated hippocampal cells. CONCLUSION: MALAT1 knockdown prevented HG-induced mTOR activation and inhibited tau phosphorylation. MALAT1 may be a therapy target for diabetes associated dementia.

Maresin1 Decreased Microglial Chemotaxis and Ameliorated Inflammation Induced by Amyloid-ß42 in Neuron-Microglia Co-Culture Models.

Inflammation resolution is regulated by specialized pro-resolving lipid mediators (SPMs) and the levels of SPMs are found decreased in Alzheimer's disease (AD) brain. We have previously found that one of the SPMs, Maresin1 (MaR1), improved neuronal survival and increase microglial phagocytosis of amyloid-ß 1-42 (Aß42); however, the mechanisms underlying the protective mechanism remain further investigation. We aim to investigate the effects of MaR1 on microglial chemotaxis and activation in this study. Both indirect and direct primary neuron and microglia co-culture system was used in this study. Our results showed MaR1 downregulated the increased microglial chemotaxis induced by Aß42. The microglial inactivation marker CD200R was downregulated by Aß42 and upregulated by MaR1. Pro-inflammatory cytokines secretion such as tumor necrosis factor (TNF)-α were increased by Aß42 and these changes were revised by MaR1 treatment. In addition, the levels of chemokine monocyte chemoattractant protein (MCP)-1 were increased while the levels of anti-inflammatory factor IL-10 secretion were decreased by Aß42, and these changes were abolished by MaR1 treatment. Moreover, by proteomics analysis, we identified cell signaling pathways affected by MaR1 were not only limited to inflammation-related pathways such as P38, but also in pathways involved in cell survival, autophagy, axon formation, and apoptosis, including PI3K/AKT, mTOR, ERK, caspase3, Cdc42, and p75NTR. In conclusion, MaR1 promoted inflammation resolution by inhibiting chemotaxis and regulating activation of microglia. MaR1 played a neuroprotective role by affecting cell signaling pathways involving inflammation, cell survival, autophagy, axon formation, and apoptosis inhibition.

Antitumor Effects of Berberine on Gliomas via Inactivation of Caspase-1-Mediated IL-1ß and IL-18 Release.

Gliomas arise in the glial cells of the brain or spine and are the most prevalent and devastating type of brain tumors. Studies of tumor immunology have established the importance of the tumor micro-environment as a driver of oncogenesis. Inflammatory mediators such as IL-1ß and IL-18 released by monocytes regulate transcriptional networks that are required for malignant cell growth. Berberine is a natural botanical alkaloid that is widely found in the Berberis species. Although it has been widely used as an anti-diarrheal treatment in North America for several decades, our study is the first to investigate berberine as an anti-tumor agent in glioma cells. In this study, we demonstrate that berberine significantly inhibits inflammatory cytokine Caspase-1 activation via ERK1/2 signaling and subsequent production of IL-1ß and IL-18 by glioma cells. Moreover, we found that berberine treatment led to decreased motility and subsequently cell death in U251 and U87 cells. In addition, our study is the first to indicate that berberine can reverse the process of epithelial-mesenchymal transition, a marker of tumor invasion. Taken together, our work supports berberine as a putative anti-tumor agent targeting glioma cells.

Onjisaponin B (OB) is Neuroprotective During Cognitive Loss Through Immune-mediated and SIRT1 Pathways.

BACKGROUND: The purpose of the present study was to investigate the effects of Onjisaponin B (OB) in lipopolysaccharide (LPS)-induced cognitive deficits. METHODS: The rats were divided into four groups: sham group, LPS group (the model group), LPS + OB (1 mg/kg) group and LPS + OB (2 mg/kg) group. OB was treated three days before surgery and thereafter continuously for 7 days. Three days later, rats were intracerebroventricularly injected with LPS. The levels of inflammatory cytokines and the capability of free radical scavenging in serum and hippocampus were determined after the LPS challenge. PC12 cells were divided into control group, LPS group (the model group), LPS + OB (10 µM) group, LPS + OB (20 µM) group, LPS + OB (40 µM) group, LPS + OB (2 mg/kg) + nicotinamide group. The cell viability was measured by MTT assay. The protein expressions of Sirt1, p-AMPK, AMPK, Nrf-2, HO-1, Bcl-2, Bax, caspase-9, caspase-3, p-IκBα, IκBα, p-NF-κBp65 and NF-κBp65 were detected by western blot analysis. RESULTS: As a result, OB administration effectively relived the cognitive impairment, reduced the contents of IL-1ß, IL-6, TNF-α, MDA and restored SOD activities of SOD in serum and hippocampus of LPS-induced rats. Furthermore, OB treatment improved cell viability, ameliorated the alterations of IL-1ß, IL-6, TNF-α, MDA and SOD in the supernatant of LPS-induced PC12 cells. Of note, the expressions of Sirt1, Nrf-2, HO-1, Bcl-2 and p-AMPK were downregulated, while Bax, caspase-9, caspase-3 and the phosphorylations of IκBα and NF-κBp65 in the LPS-stimulated hippocampus and PC12 cells were increased attributed to the LPS stimulation. Nevertheless, the conditions were significantly attenuated by OB treatment. In the LPS-induced PC12 cell, nicotinamide, a SIRT1 inhibitor, abrogated the beneficial effects of OB, as indicated by the antioxidant, anti-inflammatory and anti-apoptosis signaling. CONCLUSION: Based on the above evidence, our results demonstrated that OB was a potential therapeutic candidate for LPS-induced cognitive deficits.

Intraepidermal nerve fiber density of healthy human.

OBJECTIVES: To analyze intraepidermal nerve fiber density (IEFND) by skin biopsy, evaluate the effect of age, anatomical sites, and ethnic origin on IEFND and develop a reference range of IENFD at the distal leg of healthy human. METHODS: Seventy skin biopsy specimens from surgical procedures involving 70 patients were analyzed. Specimens were fixed routinely in formalin and thereafter embedded in paraffin. Nerve fibers of 10-µm-thick sections were observed using immunoperoxidase staining with panaxonal antibody protein gene product 9·5 (PGP 9·5). The morphology of intraepidermal nerve fibers (IENFs) and the IENFD was determined using light microscope. The statistical analysis was performed with SPSS 16·0 software. RESULTS: No significant correlation was observed between IENFD and age (Pwrist  =  0·830, Pdistal leg  =  0·478). The significant correlation was observed between IENFD and anatomic site (P  =  0·001), the IENFD of upper arm and proximal thigh were significantly higher than that of wrist and distal leg. The reference range for IENFD of distal leg in normal Chinese humans was 40·55 fibers/mm(2). The IEFND of Chinese healthy human was significantly lower than that of Finnish (62·87 ± 15·25 vs 114·617 ± 32·322 fibers/mm(2), P < 0·05). DISCUSSION: Skin biopsy may be a useful tool in sensory neuropathies. IENFD is independent of age, but varies in different parts of the body. The proximal sites have a higher IENFD, but no significant difference is found between the wrist and distal leg.